Not All FC Switches Are Created Equal

Spirent Communications has developed the first storage routing tester for Fibre Channel networks, giving OEMs, large enterprises, and service providers unprecedented ability to analyze the scalability and viability of FC switches and networks.

But what's really creating a buzz around Spirent's test are the results so far: few, if any, vendors can scale to the theoretical maximum of 239 switches.

Because it tries to maintain neutrality, Spirent isn't saying much about the results.

"As a neutral party, we cannot make a public assertion that no vendor in the industry can scale," the company says in a statement. "Of the vendors our test equipment has tested, some stop at lower numbers and some numbers go beyond 200. Spirent Communications has a policy of non-endorsement, or comment on, the merits or demerits of any specific vendor products that are tested using Spirent test solutions, nor any test results, nor the meaning of those results, achieved by any vendor."

In any case, the numbers are more about bragging rights than real-world conditions — the biggest SANs currently use only a fraction of the theoretical maximum number of switches.

"I can't think of a single SAN with more than 50 [switches] off the top of my head, and that's a big SAN," says Steve Duplessie, founder and senior analyst at Enterprise Storage Group. "Ports is what people need, not a billion switches. Big switches, big port counts equals much easier management."

SRT can simulate an entire network of up to 239 switches with a single Spirent Fibre Channel module, which the company says allows users to stress SAN equipment with more accurate and reliable test results. In the near future, the company says large SANs could exceed 1,000 ports and have more than 50 switches in a network — but still far fewer than the theoretical maximum.

Without the SRT, the only way to test has been to build a network with 50 or more real switches and then combine simulated end-devices and real end-devices, an approach Spirent calls "cumbersome, expensive, and unreliable."

"Until now, our customers have been limited to testing with the number of switches they could afford, that they could easily fit in their lab, and that they could easily set up and maintain," says Mark Fishburn, Spirent's VP of technical strategy. "By giving users access to virtually a limitless amount of switches, Spirent's SRT application enables unparalleled testing and scaling capability for next-generation storage area networks."

"As storage networks continue to grow, it is imperative that companies test their switches under real-world load conditions, especially when undertaking
storage consolidation and business continuity projects," says Jamie Gruener, senior analyst at The Yankee Group. "Testing switches under the maximum possible load configuration is important, and is something that Spirent's SRT can do easily and cost effectively."